title_bar: Simplify git-ui feature flag check (#23475)

This PR is a follow-up to
https://github.com/zed-industries/zed/pull/23470 that simplifies the way
we check the `git-ui` feature flag in the title bar.

Release Notes:

- N/A

crates/zed/src/zed.rs

@@ -389,7 +389,16 @@ fn initialize_panels(prompt_builder: Arc<PromptBuilder>, cx: &mut ViewContext<Wo
             workspace.add_panel(notification_panel, cx);
         })?;
 
-        let git_ui_enabled = git_ui::git_ui_enabled(git_ui_feature_flag).await;
+        let git_ui_enabled = {
+            let mut git_ui_feature_flag = git_ui_feature_flag.fuse();
+            let mut timeout =
+                FutureExt::fuse(smol::Timer::after(std::time::Duration::from_secs(5)));
+
+            select_biased! {
+                is_git_ui_enabled = git_ui_feature_flag => is_git_ui_enabled,
+                _ = timeout => false,
+            }
+        };
 
         let git_panel = if git_ui_enabled {
             Some(git_ui::git_panel::GitPanel::load(workspace_handle.clone(), cx.clone()).await?)